Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and readOnlyHint=false, and the description adds real behavioral context beyond that: overwrite replaces an existing target, recursive is required to remove a directory, and remove/mkdir are tolerant of missing paths. It stops short of stating permission requirements or what stat actually returns.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four terse action-prefixed clauses, front-loaded by action name, with zero filler. Every sentence contributes a distinct semantic detail.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 6-parameter mutation tool with no output schema, the action semantics are covered but the return behavior of stat ('what it is') is left vague and the sandbox-id parameter and authorization model are untouched. Adequate but with visible gaps.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is only 33%, so the description carries meaningful weight, and it does: 'to' is tied to rename, 'overwrite' is explained as the replace toggle, and 'recursive' is tied to directory removal. The 'id' and 'action' parameters are self-evident, so the ambiguous booleans are the ones that matter and they are covered.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description enumerates the four actions (stat, mkdir, rename, remove) with a concrete effect for each, so an agent knows exactly what the tool does. It distinguishes the tool from read/write/list siblings via the action vocabulary, though it does not name alternatives explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the per-action breakdown rather than stated as when-to-use guidance, and no sibling alternative (e.g. files_read, files_write) is named as a fallback. The note that missing paths are not errors for remove/mkdir is a useful operational hint but not routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.